While Apple Computer grabs publicity for its new 99 cent music download store, Microsoft is quietly preparing for a counterattack by improving its own technology for supporting subscription music services.

Services such as Pressplay, which uses Microsoft technology, have been put on the defensive with news that Apple has sold more than 2 million downloads since April 28, the day its iTunes Music Store launched. But Microsoft is betting that new security enhancements planned for later this year could make renting music, rather than owning it, more attractive to consumers.

Microsoft said it is developing software that makes it easier for subscription services to transfer music to portable music players. These services now provide unlimited downloads of hundreds of thousands of songs to a PC for a monthly fee, but they typically do not allow files to be moved around much. Microsoft said it will soon address this shortcoming with technology that will allow unlimited downloads to a portable device--a dramatic improvement.

"We can already support unlimited downloads tethered to the PC," said Jonathan Usher, director of Microsoft's Windows Media division. "The next step is enabling access to unlimited downloads on consumer devices."